class_docstr: Gini Impurity split criterion.
code: def num_subsets_greater_than_frac(distributions, min_frac):
      total_weight = 0.0
      dist_sums = [0.0] * len(distributions)
      for i in range(len(dist_sums)):
          dist_sums[i] = sum(distributions[i].values())
          total_weight += dist_sums[i]
      num_greater = 0
  
      if total_weight > 0:
          for d in dist_sums:
              if (d / total_weight) > min_frac:
                  num_greater += 1
      return num_greater
  
file_path: river/river/tree/split_criterion/gini_split_criterion.py
imports: from __future__ import annotations
  import math
  from .base import SplitCriterion
label_desc: Use image node_id 5 for calling the GiniSplitCriterion obj's underlying member method code with example usage: obj.num_subsets_greater_than_frac(distributions, min_frac) and returns: num_greater